Yes, sorry, I was careless.
Maria Ball married Robert Tyser on 8 February 1804; she was buried on 13 February 1805. I also assumed she must have died in childbirth, although there were plenty of other possible causes at that time, eg TB, but I haven't found any baby that fits (loads of other baby Tysers, but born to Robert's brothers/cousins around Barking).
RT then married Maria Walter on 5 October 1805.
The first son, Robert Walter Tyser, was born on 7 September 1806. Henry followed 22 March 1808, George 1810, John 1811, Louisa 1812, Maria 1816.
Mother Maria died 1817.
Yes Maria is pretty prevalent in the family. My guess is that it was probably pronounced Mar-eye-a (in my family of Protestants, that was how my aunt's name was used). My own name, Georgina, was also pronounced differently at that time.
Maria Walter's mother was also Maria: Anna Maria Walter nee Brasier.
I hope I've now got it all right. I have a tree on Ancestry co.uk btw.